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Felicuda have for their base shoerl in mass; but it is true that other congenerous lavas of the same island, which form as it were walls perpendicular to the sea, are smooth over their whole superficies. A similar smoothness is observable in some of those of Mount Etna, on the shore between. Messina and Catania, which bavjT for their base the horn-stone; though others extremely resembling them, between Jaci Reale and Catania, are formed in prisms.
"Compactness and solidity are, likewise, not a necessary condition in lavas,- to this appropriate crystallization. This has already been remarked by M. Dolomieu; and I have obserVed that many amorphous lavas on the shores of several of the Eolian islands are more compact than the prismatic lavas of Felicuda.
"What then can be the intrinsic circumstance of the lava which determines it thus to cleave in the prismatic form? I confess I am ignorant: and who can say that we do not seek it in vain within the lava, since it may be extrinsic ttnd adventitious? Such, certainly, appears to be the opinion of M. de Luc; and, more expiessly, that of M. Dolomieu, who, to explain the phenomenon of volcanic prisms, has recouise to a sudden congelation, and instantaneous contraction of lavas.
"The facts which we have adduced relative to lavas, both prismatic and not prismatic, it has been seen, do not always accord with those related by the French naturalist, but even on this supposition, ^which is incontestable, may we not retain the same principle of explanation, which, to say the truth, appears to be sufficient, with some requisite modifi
cations f These I will endeavour to suggest, illustrating my conjecture by the two cases above adduced; the one, that of the lavas which lake the form of prisms merely from the contact of the at' mosphere, as in Vulcaoo and near the summit of Etna ; the other, that of the lavas which refuse to take such a form even within the sea, as at Ischia,. in some parts of the base of Etna, and in all the Eolian isles except Felicuda.
As to the former, may not a sudden coagulation and contraction have taken place in some lavas from the mere influence of the atmosphere, though the lava was not included in any cleft or fissure? It is sufficient that it be suddenly deprived of the caloric (heat) by which it is penetrated, and which rendered it rarefied and fluid. To this deprivation a lava of little thickness will be very liable; since a body loses its beat the sooner, the less its thickness and density. This sudden contraction may also be produced by the circumstances of the atmosphere ; as should a strong wind, of a very cold temperature, blow at the time the melted lavas in our crucibles will be found to give greater weight to this latter conjecture. If they are taken from the furnace, and caused to pass through a beat gradually less ; their surface as they cool, will only split into a few cracks,-of little depth, arid usaally irregular; but, when they are immediately, in the winter time, carried into the cold air, the fissures, besides being deeper, will frequently be disposed in snch a manner, as to foim small polyheclrous prisms, which may easily be detached from the rest of the lava. '•' With respect to those lavas which do not assume a prismatic form, though they fall into the sea, it is certain that, to take that con. formation, their mass must have a strong degree of effervescence and dilatation, and that it must be deeply penetrated with the igneous Quid, otherwise the contraction necessary to produce prisms cannot take place. But many currents which descend from the summit of burning mountains to the sea, must have lust their effervescence with their heat in so long a course, and scarcely retain sufficient to continue their motion downwards, which, perhaps, would cease, were it not for the impelling gtavity of
the lava, which frequently falls into the sea perpendicularly.
"Such is tht; hypothesis Ly which I would explain the cause why some lavas have assumed a prismatic contonnation without any concurrence oi the sea-water, and uthereeKuib.it no appearance of it in places where they have lmmerged inEo the sea. I nevertheless leave every one to form his own opinion; and should an explanation at these imp rtant tads be discovered, preferable to mine, whuu I consider as only conjectural, i shall receive the communication of it with sincere gratitude, and adopt it with pleasure."
Geological Facts, corroborative of the Mosaic Account of the Deluge, with an iNQumy into the Origin, Pkouiiess, and still Permanent Consequences of that Catastrophe, by Richard Kirwan, Esq. LL.D. t'.R.S. and M.R.I.A.
[From the sixth Volume Qf the Transactions of the Royal Irish
which is true, for probably its original beat was the same as that of many islands in the same latitude at this day, but still it was too cold for elephants and rhinoceri, aud between the climates which they might have then inhabited and the places they are now found in too many mountains intercede to suppose them brought thither by any other means but a general inundation. Besides, Siberia must have attained its present temperature at the time these animals were transported else they must have all long ago putiiiied.
"3dly, Shells known to belong ► to shores under climates very distant from each other are in sundry places found mixed promiscuously with each other; one sort of them, therefore, must have been transported by an inundation; the promiscuous mixture can be accounted for on no other supposition.
"These appear to me the most unequivocal geologic proofs of a general deluge. To other facts generally adduced to prove it, another origin may be ascribed; thus the bones of elephants found in Italy, France, Germany, and England, might be the remains of some brought to Italy by Pyrrhus or the Carthaginians, or of those employed by the Romans themselves; some are said to have been brought to F.ngland by Claudius. 4 Phil. Trans. Abr. 2d part, 242. When these bones, however, are accompanied with marine remains, their origin is no longer ambiguous. Thus also the bones and teeth of whales, found near Maestriclit, are not decisively of diluvian origin, as whales have often been brought down as low as lat. 48°. 34 Roz. 201. Nay sometimes they strike on the coast of Italy. 1 Targioni Tozzetti, 386.
"Yet to explain the least ambiguous of these phenomena, without having recourse to an universal deluge, various hypotheses have been framed.
"Some have imagined that the axis of the earth was originally parallel to that of the ecliptic, which would produce a perpetual spring in every latitude, and consequently that elephants might exist in all of them. But the ablest astronomers having demonstrated the impossibility of this parallelism, it is unnecessary to examine its consequences; it only deserves notice that the obliquity of the equator is rather diminishing than increasing. See La Lande in 44 Roz. 212. Besides, why are these bones accompanied by marine remains? Others, from this nutation of the earth's axis, have supposed that its poles are continually shifting, and consequently that they might have originally been where the equator now is, and the equator where the poles now are; thus Siberia might have, in its turn, been under the equator. But as the nutation of the earth's axis is retrogressive every nine years, aud never exceeds ten degrees, this hypothesis is equally rejected by astronomers. 44 Rat. 210. 2 Berguni. Erde Kugel, 305. The pyramids of Egypt demonstrate that the poles have remained unaltered these three thousandjears.
"The 3d hypothesis is that of Mr. Buffon. to which the unfortunate Bailly has done the honour of acceding; according to him the earth, having been originally in a state of fusion, and for many years red hot, at last cooled down to the degree that rendered it habitable. This hypothesis he was led to imagine from the necessity of admitting that the globe was, at least to a certain distance beneath its surface, originally in a soft state; the solution of its solid parts in water he thought impossible, falsely imagining that the whole globe must have been in a state of solution, whereas the figure of the earth requires the liquidity of it only a few miles beneath its surface. Epoques, 10 and 35. It he had trod the path of experiments, he would have found both the hardness and transparency, of what he calls his primitive glass, and thinks the primitive substance of the globe, namely quartz, to be altered in a strong heat with a loss of 3 per cent, of its weight, and that so far from having been a glass, it is absolutely infusible. The loss of weight he must have seen, could be ascribed to nothing else but the loss of its watery particles, and that therefore it must have been originally formed in water; he would have found that some feldtspars lose 40 per cent, and others at least 2 per cent, by heat; he would have perceived that mica, which he thinks only an exfoliation of quartz, to be in its composition essentially different. He certainly found their crystallisation inexplicable, for he does not even attempt to explain it. ** But waving this, and a multitude of other insuperable difficulties in his hypothesis, and adverting only to the solution he thinks his' theory afl'ords, of the phenomenon of the existence of the bones of elephants, and the carcase of a rhinoceros iii Siberia, I say it is defective even in that respect. For allowing his supposition that Siberia was at any time ot a temperature so suited to the constitution of Uiese animals that they might live in it, yet the remains lately found in that country cannot be supposed to belong to animals that ever lived in it:
"1st, Because though they are found at the distance of several hundred miles from the sea, yet they are surrounded by genuine marine vegetables, which shews that they were brought thither together with those vegetables.
"2dly, Because they are generally found in accumulated heaps, and it is not to be imagined that while alive they sought a common burialplace no more than they at present do in India.
"3dly, Because the rhinoceros was found intire and unputrified, whereas if the country was warm when he perished, this could not have happened.
"4tbly, Because in no very distant latitude, namely that of Greenland, the bones of whales, and not of elephauts, are found on the mountains, consequently that latitude must have been in that ancient period sufficiently cold to maintain whales, as it is at this day; and that cold we know to be very considerable, and incompatible with the proximity of a climate suited to elephants. 17 N. Comment. Petropol. 576. 1 Act. Petrop. 55. Kenov. 73. Therefore the animals whose remains are now found in Siberia could not have lived in it.
"The 4th hypothesis is that of Mr. Edward King, but much amplified and enlarged by Mr. de Luc. This justly celebrated philosopher is of opinion that the actual continents were, before the deluge, the bottom or bed of the ancient ocean, and that the deluge consisted in the submersiou of the ancient continents, which consequently form the bottom orbed of our actual oceans, consequently our actual mountains were all formed in the antediluvian ocean, and thus shells might be left on their highest summits.
"Tin tbis hypothesis the ancient continents must have, existed in those tracts now covered by the Atlantic and ParifiV Oceans; if so, I do not see hiTM the elephants could have been bn ughl m'o Siberia, or a whole rhinoceros found in it: for Siberia being then the bottom of Some ocean the Sea must have moved from it to cover the sinking continents, instead of moving towards it, to strew over it their spoils.—If it be said that these anifnals were tarried into the sea hefore the flood, then, assuredly, the rhinoceros should have be< n devoured, and only his bones left.
"To say nothing of the incompatibility of this system with the principal geologic phenomena, mentioned in my former essav, and of the destruction of at least all the graminivorous fish that must have followed from their transfer to a soil not suited to them, it is evidently inconsistent with the Mosaic account of this catastrophe, which account these philosopbi rs however admit.
"Moses ascribes the deluge to two principal causes, a continual rain for forty days, and the eruption of the waters of the great abyss. Now to what purpose a rain of forty days to overwhelm a continent that was to be immersed under a whole ocean? He tells trs the waters increased on the continents a certain number of days, rested thereon another period of flays, and then returned. Do not these expressions imply a permanent ground on which they increased and rested, and from which they Sfterwards retreated? As the retreat followed the advance, is it not clear that-they retreated from the same spaces on which they had before advanced and restedi
"Mr. de Luc replies, that m the 13th verse of the 6th chapter -of
Genesis, it is said the earth should be destroyed, and that Mr. Michaelis so transl iteB it. However, it is plain, from what has been just mentiohed, that Moses did not understand suchadesiroction assttouH cause it to disappear totally and for ever; he tells us that the waters stood 15 cubits over the highest mountains; now as he has no where mentioned the antediluvian mountains, but has the postdiluvian, it is plain that it is to these bis narration relates, and these he tells us were at the time of the deluge covered with water, an.l uncovered when the waters diminished; he never distinguished the postdiluvian ■from the antediluvian, and therefore must have considered them as the same.
"Nor did Noah himself believe the ancient continents destroyed, for he took the appearance ot an olive branch to be a s.-gn of the diminution of the flood. This be certainly believed to have grown on the ancient continent, and could not expect it to have shot up from the bottom of the sea.—Mr. de Luc tells us that this olive grew on an 'antediluvian island, and that these islands, being part of the antediluvian ocean, were not flooded —it is plain, however, Noah did not think so, else he would not judge the appearance Ot the olive to be a sign of the diminution of the waters.—Where is it mentioned or wh:it renders it necessary to infer that islands existed before the flood? If islands did exist, and were to esenpe the flood, so might their inhabitants also, contrary to the express words of the text.
"It would surely be much more convenient for Noah, his 'family, and animals, to have taken refuge in one of them, than to renrnin pent up in the ark.